The present invention relates to a crusher provided on a mobile vehicle body.
As an example is shown in FIG. 11, a mobile crusher has a hopper 2 provided on a mobile vehicle body 1, a feeder 3 provided at a bottom portion of the hopper 2, a crusher member 4 provided under an end portion of the feeder 3, a belt conveyor 5 provided under the crusher member 4, and the like. The feeder 3, the crusher member 4, and the belt conveyor 5 are driven by a feeder driving system, a crusher driving system, and a belt conveyor driving system (each not illustrated). An upper portion of the crusher member 4 is opened and faces to the end portion of the feeder 3, and a lower portion of the crusher member 4 is opened and faces to a top surface of the belt conveyor 5. According to the above configuration, a material 6a to be crushed, which is placed on the feeder 3 from the outside, is fed into the crusher member 4 from the upper opening of the crusher member 4 by the drive of the feeder 3, and is crushed by the drive of the crusher member 4. A crushed material 6b is discharged onto the belt conveyor 5 from the lower opening of the crusher member 4 and is discharged out of the vehicle by the drive of the belt conveyor 5, as a product.
In the above mobile crusher, a synchronous control of the aforementioned three driving systems has a profound effect on the productivity of the crushed material 6b. Thus, some crushers have target crushing amount setting means (not illustrated) for inputting a target crushing amount A2 per unit time of the crusher 4, and actual crushing amount detecting means (not illustrated) for detecting an actual crushing amount B per unit time of the crusher 4. The crusher further has control means for comparing the target crushing amount A2 and the actual crushing amount B, then as shown in FIG. 12, increasing the speed of the feeder 3 when xe2x80x9cA2xe2x88x92B greater than 0xe2x80x9d, maintaining a driving speed V of the feeder 3 when xe2x80x9cA2xe2x88x92B=0xe2x80x9d, and decreasing the speed when xe2x80x9cA2xe2x88x92B less than 0xe2x80x9d. It should be noted that xe2x80x9cA2xe2x80x9d has a predetermined range. Further, the following crushers are known.
(1)A crusher described in Japanese Utility Model Laid-open No. 5-1315 is a stationary type, which has a sensor for detecting a rock when the large rock stays on a grizzly screen provided at the upper opening of the crusher, and a controlling device for automatically stopping the feeder when the sensor detects the rock for a predetermined time.
(2) A mobile crusher described in Japanese Patent Laid-open No. 7-116541 has a sensor for detecting overloading when a crusher is under over load, and a controlling device for automatically stopping the feeder when the sensor detects the overloading.
(3) A mobile crusher described in Japanese Patent Laid-open No. 8-281140 has a sensor for detecting an anomaly when the anomaly occurs at each component (including not only the feeder driving system, crusher driving system, and the belt conveyor driving system, but also an engine, a water temperature in a generator and the like, oil hydraulic pressure, residual amount of fuel, and the like), and a controlling device for automatically stopping the feeder when the sensor detects an anomaly.
According to the above prior arts, though they respectively contribute to productivity improvements, they have the following disadvantages.
(1) Though the details are described later, the actual crushing amount B directly depends on the amount of the material 6a to be crushed inside the crusher member 4 from the view of the placement position of the crusher member 4 and from the view of the crushing efficiency of the crusher member 4. In spite of this, in the above conventional crusher, specifically, the crusher, which changes the driving speed V of the feeder 3 based on the comparison result between the target crushing amount A2 and the actual crushing amount B, the detection result of the actual crushing amount detecting means provided at a downstream side of the crusher member 4 is reflected in the driving speed V of the feeder 3 provided at an upstream side of the crushing member 4. As a result, a lag inevitably occurs in the synchronization between the actual crushing amount B and the driving speed V of the feeder 3. Thereby the disadvantage that the control of high quality is not obtained is caused.
(2) In the crusher described in each of the aforementioned Official Gazettes, the feeder automatically stops when an anomaly occurs. Specifically, these prior arts are control arts when an anomaly occurs. Thus, the disadvantage occurs, in which, for example, a damage to the crusher itself and reduction of productivity are caused.
In view of the aforementioned prior arts, an object of the present invention is to provide a mobile crusher which has a high-quality controlling function enabling efficient production, and which is capable of preventing the crusher itself and the like from being damaged, by preventing the occurrence of an anomaly.
The mobile crusher according to the present invention is made especially in view of the above xe2x80x9cthe actual crushing amount B directly depends on the amount of the material 6a to be crushed inside the crusher member 4xe2x80x9d. This will be explained with reference to a jaw crusher in FIG. 1A to FIG. 3.
A jaw crusher 4 is one which is also placed on the example machine in FIG. 11, and as shown in FIG. 1A, FIG. 2A and FIG. 3, a stationary plate 4a and a swing jaw 4b are adjustably placed to face to each other with an upper opening being large and a lower opening being small. A material 6a to be crushed is fed into a portion between the stationary plate 4a and the swing jaw 4b facing to each other (being the aforementioned xe2x80x9can inside of the crusher member 4xe2x80x9d, and a so-called xe2x80x9ccrushing chamberxe2x80x9d). A grain diameter of a crushed material 6b is determined by the dimension of the lower opening.
[1] As shown in FIG. 1A, the stationary plate 4a is fixed to a vehicle body (not illustrated), but an upper end of the swing jaw 4b is rotationally driven by an eccentric driving shaft 4c, and a lower end thereof is freely supported by the vehicle body via a plate 4d. Specifically, as shown in a skeleton drawing of linkage in FIG. 1B, the movement of the swing jaw 4b approaches a linear movement a3 as a circular movement a1 at an upper portion by the eccentric driving shaft 4c proceeds to a lower portion. Accordingly, a crushing force F0 per one rotation of the eccentric driving shaft 4c produced by the swing jaw 4b (specifically, the force F0 in a vertical direction to the stationary plate 4a) is distributed as shown in FIG. 1C.
[2] Assume that stones from a small stone (small material to be crushed) 6a to a large stone (large material to be crushed) 6a are orderly fed into the inside of the crusher member 4 from the small lower portion toward the large upper portion as shown in FIG. 2A. In this situation, a crushing force F1 required for crushing each stone 6a is distributed as shown in FIG. 2B. When the distribution (FIG. 2B) of the required crushing force F1 is overlaid on the distribution of the crushing force F0 produced by the swing jaw 4b in FIG. 1C, FIG. 2C is obtained. FIG. 2C shows that when a height H of the material 6a to be crushed inside the crusher member 4 is large, the material 6a to be crushed cannot be efficiently crushed. It should be noted that the amount of the material 6a to be crushed inside the crusher member 4 is equivalent to the height H (the same shall apply hereinafter).
[3] Assume that small stones 6a are fed into the inside of the crusher member 4 to fill the same as shown in FIG. 3. In this situation, the stones 6a from the center to the lower portion of the crusher member 4 directly receive the crushing force F0 and are crushed, since the crushing movement in this area gradually approaches the linear movement a3 (See FIG. 1B), and thus the power loss is small. However, as for the stones 6a at the upper portion of the crusher member 4, since the crushing movement in this area is the circular movement a1, the crushing force F0 has the components changing into the rotational movement of each stone 6a itself, and the frictional force between the stones 6a, and thus the expected crushing cannot be acheived. Specifically, not only the power loss occurs to the stones 6a at the upper portion of the crusher member 4, but also the wear of the upper portions of the stationary plate 4a and the swing jaw 4b is promoted.
[4] As is obvious from the explanations in the above [2] and [3], the height H of the material 6a to be crushed inside the crusher member 4 is basically desired to be the height which does not include the upper portion of the inside of the crusher member 4 for efficiency of the crusher member 4 (hereinafter, the upper limit height H is called xe2x80x9cheight HHxe2x80x9d. See FIG. 2C).
[5] The actual crushing amount B is an absolute amount, and is not related to the efficiency of the crusher member 4. Consequently, even if the crushing efficiency is favorable in view of the crushing force F0 of the c rusher member 4, if the crushing amount B is actually small, it is meaningless. Specifically, based on the above explanations [2] and [3], if the height H of the material 6a to be crushed inside the crusher member 4 is set at the lower portion of the crusher member 4, it frequently happens that the material 6a to be crushed does not exist inside the crusher member 4. Since the crushed material 6b falls as a result of being pressed by the weight of itself and the weight of the material 6a to be crushed at the upper portion, if the material 6a to be crushed doesn""t exist at the upper portion, control of the producing speed or the like becomes difficult. Specifically, the height H of the material 6a to be crushed inside the crusher 4 is desired to be basically the height which doesn""t include the lower portion inside the crusher member 4 if the actual crushing amount B is considered (Hereinafter, the lower limit height H is called xe2x80x9cthe height HLxe2x80x9d. See FIG. 2C).
[6] According to the above [4] and [5], in point of efficiency of the crusher member 4, and in point of the actual crushing amount B, it can be understood that the height H of the material 6a to be crushed inside the crusher 4 is desired to be set as xe2x80x9cHL less than H less than HHxe2x80x9d (See FIG. 2C). xe2x80x9cHLxe2x80x9d in the embodiments described later is set to be about one third of the height of the inside of the crusher member 4, and xe2x80x9cHHxe2x80x9d is set to be about two thirds of the height.
[7] As for the crusher member 4, other than the above jaw crusher, various kinds of crusher members such as, for example, an impact type, shear type and the like are prepared. The impact type has a rotary plate and a crushed material discharge port at a lower portion of a crushing chamber, and a repulsion plate and an input port for the material to be crushed at an upper portion, and is the type in which the material to be crushed from the input port is repulsed by the rotary plate, is smashed to the repulsion plate to be crushed, and is discharged from the discharge port. The shear type is the type in which the material to be crushed is fed into a portion between rollers rotating reversely to each other separated by a predetermined distance to be crushed, and is discharged from the lower portion. The conclusion of the above [6] (HL less than H less than HH) is also applicable to these impact type, the shear type and the like of crusher member 4 by detecting the height H of the material 6a to be crushed inside the crusher member 4.
In order to attain the aforementioned object, a first aspect of a mobile crusher according to the present invention is a mobile crusher including a feeder and a crusher member each set drivably on a mobile vehicle body, which feeds a material to be crushed, which is placed on the feeder from an outside, into an inside of the crusher member from an upper opening of the crusher member by drive of the feeder, crushes the same by drive of the crusher member, and discharges a crushed material from a lower opening of the crusher member to the outside, and is characterized by including:
(a) means for detecting an amount of a material to be crushed, which detects an amount H of the material to be crushed inside said crusher member; and
(b) control means for receiving the amount H from the means for detecting the amount of the material to be crushed and controlling a driving speed V of the feeder changeably based on the reception amount H.
According to the aforementioned first configuration, since the driving speed V of the feeder is directly controlled according to the amount H of the material to be crushed, occurrence of an anomaly can be prevented, and thus the crusher itself or the like can be prevented from being damaged. The quality of the control of the actual crushing amount B is improved, thus making it possible to efficiently produce the crushed objects.
A second aspect is a mobile crusher including a feeder and a crusher member each set drivably on a mobile vehicle body, which feeds a material to be crushed, which is placed on the feeder from an outside, into an inside of the crusher member from an upper opening of the crusher member by drive of the feeder, crushes the same by drive of the crusher member, and discharges a crushed material from a lower opening of the crusher member to the outside, and is characterized by including:
(a) means for detecting an amount of a material to be crushed, which detects an amount H of the material to be crushed inside the crusher member; and
(b) control means for previously memorizing reference values HL and HH (note that xe2x80x9cHL less than HHxe2x80x9d), receiving the amount H from the means for detecting the amount of the material to be crushed, comparing the amount H with the reference values HL and HH, and
(b1) when xe2x80x9cH less than HLxe2x80x9d, inputting a signal +xcex94I to increase a driving speed V of the feeder to a feeder driving system,
(b2) when xe2x80x9cHL less than H less than HHxe2x80x9d, inputting a signal I2 to maintain the driving speed V to the feeder driving system, and
(b3) when xe2x80x9cHxe2x89xa7HHxe2x80x9d, inputting a signal xe2x88x92xcex94I to decrease the driving speed V to the feeder driving system.
The above second configuration is a result of embodying the above first configuration further in detail, and the result is as shown, for example, in the control result in FIG. 6. Specifically, the height H of the material to be crushed inside the crusher member is basically maintained to be xe2x80x9cHL less than H less than HHxe2x80x9d. As a result, the most preferable mode is achieved in terms of the efficiency of the crusher member and the actual crushing amount B.
A third aspect is a mobile crusher including a feeder and a crusher member each set drivably on a mobile vehicle body, which feeds a material to be crushed, which is placed on the feeder from an outside, into an inside of the crusher member from an upper opening of the crusher member by drive of the feeder, crushes the same by drive of the crusher member, and discharges a crushed material from a lower opening of the crusher member to the outside, and is characterized by including:
(a) target crushing amount setting means for setting a target crushing amount A2 per unit time of the crusher member;
(b) actual crushing amount detecting means for detecting an actual crushing amount B per unit time of the crusher member;
(c) means for detecting an amount of a material to be crushed, which detects an amount H of the material to be crushed inside the crusher member; and
(d) control means for receiving a target crushing amount A2 from the target crushing amount setting means, an actual crushing amount B from the actual crushing amount detecting means, and the amount H from the means for detecting the amount of the material to be crushed, and controlling a driving speed V of the feeder changeably based on the reception amounts A2, B and H.
According to the above third configuration, in the mobile crusher having the target crushing amount setting means for setting the target crushing amount A2 per unit time of the crusher member, and the actual crushing amount detecting means for detecting the actual crushing amount B per unit time of the crusher member, in addition to the basic operational effects of maintaining xe2x80x9cHL less than H less than HHxe2x80x9d in the first and second configuration, the operational effect of rapid convergence on xe2x80x9cB=A2xe2x80x9d is provided.
A fourth aspect is a mobile crusher including a feeder and a crusher member each set drivably on a mobile vehicle body, which feeds a material to be crushed, which is placed on the feeder from an outside, into an inside of the crusher member from an upper opening of the crusher member by drive of the feeder, crushes the same by drive of the crusher member, and discharges a crushed material from a lower opening of the crusher member to the outside, and is characterized by including:
(a) target crushing amount setting means for setting a target crushing amount A2 per unit time of the crusher member;
(b) actual crushing amount detecting means for detecting an actual crushing amount B per unit time of the crusher member;
(c) means for detecting an amount of a material to be crushed, which detects an amount H of the material to be crushed inside the crusher member; and
(d) control means for previously memorizing reference values HML and HMH (note that xe2x80x9cHML less than HMHxe2x80x9d),
(d11) a correction amount +C which is set correspondingly to a value not more than the reference value HML,
(d12) a correction amount C (=0) which corresponds to a value between the reference values HML and HMH, and
(d13) a correction amount xe2x88x92C which is set correspondingly to a value not less than the reference value HMH, receiving a target crushing amount A2 from the target crushing amount setting means, an actual crushing amount B from the actual crushing amount detecting means, and the amount H from the means for detecting the amount of the material to be crushed,
(d21) when xe2x80x9cHxe2x89xa6HMLxe2x80x9d, reading the aforementioned set correction amount +C,
(d22) when xe2x80x9cHML less than H less than HMHxe2x80x9d, reading the aforementioned corresponding correction amount C (=0), and
(d23) when xe2x80x9cHxe2x89xa7HMHxe2x80x9d, reading the aforementioned correction amount xe2x88x92C previously memorized, and computing xe2x80x9cA2xe2x88x92B+ the correction amount=Dxe2x80x9d, and
(d31) when xe2x80x9cD=0xe2x80x9d, inputting a signal +xcex94I0 to increase a driving speed V of the feeder to a feeder driving system,
(d32) when xe2x80x9cD=0xe2x80x9d, inputting a signal I2 to maintain the driving speed V to the feeder driving system, and
(d33) when xe2x80x9cD less than 0xe2x80x9d, inputting a signal xe2x88x92xcex94I0 to decrease the driving speed V to the feeder driving system.
The above fourth configuration is the configuration in which the above third configuration is embodied further in detail, and the result is as shown in the control result in, for example, FIG. 8. The details are as follows. It should be noted that the reference values HL and HH which are not described in the fourth configuration are described in FIG. 7 as well as the reference values HML and HMH in the fourth configuration. Accordingly, these reference values are also explained below, but since they have the relationship xe2x80x9cHL less than HML less than HMH less than HHxe2x80x9d, if the explanation related to the reference values HL and HH is skipped, it has no effect on the operational effects of the fourth configuration. The reference value HL is the aforementioned lower limit value of the desired height of the material to be crushed inside the crusher member, while the reference value HH is the aforementioned upper limit value of the desired height.
Specifically, since the target crushing amount A2 is an index of the actual crushing amount B which can be attained in the crusher member, even if it changes every moment according to the property of the material to be crushed (Bxe2x89xa0A2), if only xe2x80x9coptimal controlxe2x80x9d is performed, it converges on xe2x80x9cB=A2xe2x80x9d even if some changes (Bxe2x89xa0A2) occur. Such xe2x80x9coptimal controlxe2x80x9d is the fourth configuration. The correction amounts from +C to xe2x88x92C may be considered to be the correction for the target crushing amount A2, or may be considered to be the correction amount in computation for the actual crushing amount B. Each mode from the upper row to the lower row in FIG. 8 will be explained in order below.
(1) Since xe2x80x9cA2xe2x88x92B greater than 0xe2x80x9d is the state in which the actual crushing amount B is smaller than the target crushing amount A2, the driving speed V of the feeder is desired to be increased. In this situation, when xe2x80x9cHxe2x89xa6HMLxe2x80x9d, the material to be crushed inside the crusher member is rapidly gone, and crushing movement without the material to be crushed occurs, thus causing noises and a damage to the machine. Accordingly, in this situation, the driving speed V of the feeder is increased.
(2) When xe2x80x9cA2xe2x88x92B greater than 0xe2x80x9d as in the above, even if xe2x80x9cHML less than H less than HMH (specifically, C=0)xe2x80x9d, the driving speed V of the feeder is increased as in the above (1).
(3) However, even though xe2x80x9cA2xe2x88x92B greater than 0xe2x80x9d as in the above, when xe2x80x9cH greater than HMH (specifically, the correction amount xe2x88x92C)xe2x80x9d, the amount H is close to the upper limit value HH, and therefore if the driving speed V of the feeder is increased, there is the fear of xe2x80x9cH greater than HHxe2x80x9d. Thereby, the correction amount xe2x88x92C is set. The correction value xe2x88x92C is set so that the negative value gradually increases as the amount H increases. According to the amount of the correction amount xe2x88x92C, three states of xe2x80x9cA2xe2x88x92Bxe2x88x92C greater than 0xe2x80x9d, xe2x80x9cA2xe2x88x92Bxe2x88x92C=0xe2x80x9d, and xe2x80x9cA2xe2x88x92Bxe2x88x92C less than 0xe2x80x9d occur. Thus,
(3a) In xe2x80x9cA2xe2x88x92Bxe2x88x92C greater than 0xe2x80x9d, the driving speed V of the feeder is increased as in the above (1).
(3b) In xe2x80x9cA2xe2x88x92Bxe2x88x92C=0xe2x80x9d, the driving speed V of the feeder is maintained.
(3c) In xe2x80x9cA2xe2x88x92Bxe2x88x92C less than 0xe2x80x9d, there is the fear that the upper opening of the crusher member is blocked by the material to be crushed since the amount H is larger than the above (3b). Accordingly, the driving speed V of the feeder is decreased. From the above, in consideration of (3a) and (3b), since it is necessary to establish xe2x80x9cH less than HHxe2x80x9d relative to any value of the A2, it is desirable to set the negative maximum value Cmin of the C to be larger than the maximum value Amax of the target crushing amount A2.
(4) xe2x80x9cA2xe2x88x92B=0xe2x80x9d is the state in which the actual crushing amount B and the target crushing amount A2 are the same, and it is separated into the three states of xe2x80x9cHxe2x89xa6HML (specifically, the correction amount +C)xe2x80x9d, xe2x80x9cHML less than Hxe2x89xa7HMH (specifically, C=0)xe2x80x9d, and xe2x80x9cH greater than HMH (specifically, the correction amount xe2x88x92C)xe2x80x9d according to the amount of the amount H of the material to be crushed.
(4a) Since the correction amount +C shows xe2x80x9cHxe2x89xa6HMLxe2x80x9d, the driving speed V of the feeder is increased to achieve xe2x80x9cHML less than H less than HMH (specifically, C=0)xe2x80x9d.
(4b) When xe2x80x9cC=0xe2x80x9d, the driving speed V of the feeder is maintained. It is natural and the explanation is not required.
(4c) Since the correction amount xe2x88x92C shows xe2x80x9cH greater than HMHxe2x80x9d, the driving speed V of the feeder is decreased to achieve xe2x80x9cHML less than H less than HMH (specifically, C=0)xe2x80x9d, thus preventing the upper opening of the crusher member from being blocked by the material to be crushed.
(5) xe2x80x9cA2xe2x88x92B less than 0xe2x80x9d is the state in which the actual crushing amount B is larger than the target crushing amount A2, and thus it is desirable to decrease the driving speed V of the feeder. In this situation, when xe2x80x9cHxe2x89xa6HML (specifically, the correction amount +Cxe2x80x9d, it is separated into the three states of xe2x80x9cA2xe2x88x92B+C greater than 0xe2x80x9d, xe2x80x9cA2xe2x88x92B+C=0xe2x80x9d, and xe2x80x9cA2xe2x88x92B+C less than 0xe2x80x9d.
(5a) When xe2x80x9cA2xe2x88x92B+C greater than 0xe2x80x9d, since the actual crushing amount B is large, it is desirable to decrease the driving speed V of the feeder, but the driving speed V of the feeder is increased to increase the feeding amount of the material to be crushed into the crusher member. As a result, a so-called crushing movement without the material to be crushed is prevented.
(5b) When xe2x80x9cA2xe2x88x92B+C=0xe2x80x9d, the driving speed V of the feeder is maintained.
(5c) When xe2x80x9cA2xe2x88x92B+C less than 0xe2x80x9d, the driving speed V of the feeder is decreased. From the above, in consideration of (5b) and (5c), it is necessary to achieve xe2x80x9cH greater than HLxe2x80x9d relative to any value of the target crushing amount A2, and therefore it is desirable to set the maximum value Cmax of the C to be larger than the maximum value Bmax of the actual crushing amount B.
(6)When xe2x80x9cA2xe2x88x92B less than 0xe2x80x9d as in the above, if xe2x80x9cHML less than H less than HMH (specifically, C=0), the driving speed V of the feeder is increased.
(7) When xe2x80x9cA2xe2x88x92B less than 0xe2x80x9d as in the above and when xe2x80x9cHxe2x89xa7HMH (specifically, the correction amount xe2x88x92C)xe2x80x9d, it is desirable to decrease the driving speed V of the feeder since the actual crushing amount B is large, but since the amount of the material to be crushed inside the crusher member is also large, the upper opening of the crusher member is blocked by the material to be crushed according to the property of the material to be crushed. Accordingly, the driving speed V of the feeder is decreased.
Specifically, though the above (1) to (7) are each separately described, in the mobile crusher having the target crushing amount setting means for setting the target crushing amount A2 per unit time of the crusher member, the actual crushing amount detecting means for detecting the actual crushing amount B per unit time of the crusher member, the shift between the modes from the above (1) to (7) is proceeded in order. Thus, in the fourth configuration, the operational effect of rapid convergence on xe2x80x9cB=A2xe2x80x9d is provided in addition to the basic operational effect of maintaining xe2x80x9cHL less than H less than HHxe2x80x9d in the first to the third configuration.
If the correction amount +C in the above fourth configuration is set to be a fixed value and larger than the maximum value of the actual crushing amount B, and the absolute value of the correction amount xe2x88x92C is a fixed value and larger than the target crushing amount A2, in the fourth configuration,
(a) when xe2x80x9cHxe2x89xa6HMLxe2x80x9d, the driving speed V of the feeder is increased,
(b) when xe2x80x9cHML less than H  less than HMHxe2x80x9d, the driving speed V of the feeder is maintained, and
(c) when xe2x80x9cHxe2x89xa7HMHxe2x80x9d, the driving speed of the feeder is decreased, thus facilitating the control. This resultant configuration shall be also included in the above fourth configuration.
A fifth configuration is a mobile crusher including a feeder and a crusher member each set drivably on a mobile vehicle body, which feeds a material to be crushed, which is placed on the feeder from an outside, into an inside of the crusher member from an upper opening of the crusher member by drive of the feeder, crushes the same by drive of the crusher member, and discharges a crushed material from a lower opening of the crusher member to the outside, and is characterized by including:
(a) target crushing amount setting means for setting a target crushing amount A2 per unit time of the crusher member;
(b) actual crushing amount detecting means for detecting an actual crushing amount B per unit time of the crusher member;
(c) means for detecting an amount of a material to be crushed, which detects an amount H of the material to be crushed inside the crusher member; and
(d) control means for previously memorizing reference values HL and HH (note that xe2x80x9cHL less than HHxe2x80x9d), receiving the target crushing amount A2 from the target crushing amount setting means, the actual crushing amount B from the actual crushing amount detecting means, and the amount H from the means for detecting the amount of the material to be crushed, comparing the amount H with the reference values HL and HH, and
(d21) when xe2x80x9cHxe2x89xa6HLxe2x80x9d, inputting a signal +xcex94I1 to increase the driving speed V of the feeder to a feeder driving system,
(d22) when xe2x80x9cHL less than H less than HHxe2x80x9d, computing xe2x80x9cA2xe2x88x92B=Exe2x80x9d, and
(d221) when xe2x80x9cE greater than 0xe2x80x9d, inputting a signal +xcex94I2 to increase the driving speed V to the feeder driving system,
(d222) when xe2x80x9cE=0xe2x80x9d, inputting a signal I2 to maintain the driving speed V to the feeder driving system, and
(d223) when xe2x80x9cE less than 0xe2x80x9d, inputting a signal xe2x88x92xcex94I2 to decrease the driving speed V to the feeder driving system, and
(d23) when xe2x80x9cHxe2x89xa7HHxe2x80x9d, inputting a signal xe2x88x92xcex94I1 to decrease the driving speed V to the feeder driving system.
The above fifth configuration is the configuration in which the feature of the correction amounts +C to xe2x88x92C is deleted, and the target crushing amount A2 and the actual crushing amount B are directly introduced. In this manner, the operational effect of rapidly converging on xe2x80x9cB=A2xe2x80x9d is provided in addition to the basic operational effect of maintaining xe2x80x9cHL less than H less than HHxe2x80x9d. In the fifth configuration, the reference value is set to be xe2x80x9cHL, HH (note that xe2x80x9cHL less than HHxe2x80x9d), but they may be replaced by xe2x80x9cHML, HMH (note that HML less than HH). This is because they are only the symbols for showing the dimensional relationship.